Checker for blast furnace stoves



March 24, 1936. E MacDoNALD RNAGE sTovJssv Filed March 2,

CHECKER FOR BLAST FU INVENTOR Patentedl Mar. 24, 1936 UNITED STATES PATENT OFFICE 2 Claims.

My invention relatesto checker structures that are particularly suitable for use with blast furnace stoves, but which can also be employed with open hearth and other furnaces.

In the building of checker work of the class referred to, bricks of rectangular form have been frequently employed, but because of their at surfaces, they cannot absorb and give off heat as rapidly as structures wherein the gas-contacting surfaces of the bricks are of non-planular form, and `have what, in effect, are projections that will becoin'e heated quickly to high temperatures by the hot gases, and which will give off heat rapidly when the direction of ow through the checker work is reversed.

While bricks having gas-contacting faces of irregular form have heretofore been made, they have been expensive to manufacture, and in some cases, cause excessive turbulence by creating cross currents of the gases, so as to greatly reduce the velocity of the air or gas. Separately-formed inserts have also been placed in the ilues formed by the bricks, but these have been expensive to manufacture and require much extra cost in handling and laying. Furthermore, the inserts themselves tend to prevent the gas `and air flowing at the desired velocities.

One object of my invention is to provide checker work having bricks of such form that they can be set up with substantially the same facility as ordinary rectangular bricks, but which nevertheless have ribs or similar projections formed thereon inV such manner that they can be manufactured at little or no greater expense than ordinary rectangular bricks. j

Another object of my invention is to provide bricks having projections that will be very effective in the absorption of and the giving oi of heat, and which will nevertheless not unduly interfere with free movement of air and gas through the checker-work, and wherein the projections will assist in properly aligning the bricks during building of the checker work, and will also assist in maintaining the bricks in position.

Another object of my invention is to provide specially-formed bricks that can be readily assembled to form graduated flue areas, and wherein there are no flat surfaces or offsets upon which deposits may readily accumulate, but wherein a desired degree of turbulence on the gas or air stream is effected to cause various portions thereof to come into contact with the heating surfaces of the brick.

Still another object of my invention is to provide checker bricks of such form that they have maximum area for supporting vertical loads, and which can conveniently be reclaimed when replacing checker work.

Some of the forms which my invention may take are shown in the accompanying drawing 5 wherein Figure 1 is a vertical sectional view through a blast furnace stove; Fig. 2 is a View taken on the line II of Fig. 1; Fig. 3 is an enlarged plan view of one of the bricks of Fig. 2; Fig. 4 is a view taken on the line IV of Fig. 1; 10 Fig. 5 is an enlarged plan view of one of the bricks of Fig. 4; Fig. 6 4is a View taken on the line VI of Fig. 1; Fig. 7 is an enlarged view of one of the bricks of Fig. 6; Fig. 8 is a view taken on the line VIII of Fig. 1; Fig. 9 is an enlarged 15 plan view of one of the bricks of Fig. 8; Fig. 10 is a face view showing the general appearance of one of the bricks of Figs. 4 to 9; Fig. 11 represents plan and face views of a modied form of brick; Fig. 12 represents plan, face and edge 20 views of still another form of brick; Fig. 13 shows plan, face and edge views of a further modification, and Fig. 14 is a sectional view showing still a further modification.

As shown in Fig. 1, the checker bricks are arranged in four zones-the bricks of Figs. 8 and 9 appearing in the lowermost or rst zone, and the bricks of Figs. 6 and '7 appearing in the next or second zone-the bricks of Figs. 4 and 5 appearing in the third zone, and the fourth and uppermost zone being composed of the bricks of Figs. 2 and 3. It will be noted that the crosssectional areas of the ues are of gradually reduced diameter from the top to the bottom of the checker chamber, so that as the hot gases flow'down through the checker work and become cooled through absorption of heat by the checker bricks, the lessening in volume of the gases will be substantially in accordance with the reduction in flue area as between successive sections. 40 The gases when they reach the bottom series of checker bricks will, of course, be considerably cooled, and not require so much flue area.

Conversely, when cold air or gases enter the bottom of the checker chamber, they will absorb heat from the checker brick and expand during -their upward travel. By this arrangement, a proper velocity of the air or gas and effective contact thereof with the bricks will be maintained.

The bricks I6 of Figs. 2 and 3may be o1 plain rectangular form, and all of substantially the same size. The bricks I1 which form the next zone have two pairs of ribs I8 formed on each Side thereof, and extending vertically approximately the full /lengths of the bricks, although they may be tapered or beveled at their upper ends, so that the upper ends of such bricks will have their side faces ush with the side faces of the bricks I6. `Also, the upper edges of the topmost course of bricks I6 may be bevelled or of wedge shape in order to eliminate fiat surfaces on which dirt Aand other deposits could accumulate.

The vertical mid portions ofthe bricks I'I are flat, so as to provide seating surfaces for the edges of the adjacent bricks, as shown at I9. 'I'he ribs at either side of the said iiat surfaces assist in retaining the abutting bricks in position, and facilitate the laying of the bricks in proper alignment.

The bricks 2i of Figs. 6 and 7 constitute the second zone of the checker chamber, while the bricks 22 of Figs. 8 and 9 are employed in the bottom zone of the checker chamber. The bricks 2| and 22 are of the same general form as the bricks of Fig. 4, but have their-ribs of greater thickness and width, so as to eiiect the desired changes in eifective flue area, as above-explained.

The bricks of the various courses may be of any suitable length in vertical directions, and a desired number of horizontal courses of each size of bricks may be laid, depending upon the vertical length of zone required.

The checker work is supported on arches 24, and rider bars 25 which may be of any suitable well-lmown form are provided, the bars being of a thickness corresponding approximately to the thiclmess of the checker bricks and placed so 'as to not obstruct the flue passages. A

The vertical ribs I8 of the various bricks form l vertically-extending recesses or grooves that produce some turbulence in the gas stream, causing all portions of the stream to be broughtv into direct contact with the bricks, without too greatly retarding the flow of the gases. Also, they readily absorb and give oi heat and present a much wider flue area for contacting the gases than if the ue openings were of rectangular form in cross section.

For example, in the case of the bottom zone, and with bricks of a given size, if thev ue openings wre of rectangular form as in Fig. 2, having the same horizontal dimensions as the overall Y horizontal dimensions of the ues of Fig. 8, there would be but 16 square inches of brick surface exposed to the gas surface per flue, as against 22 square inches with the ribbed bricks 22 of Fig. 8. In other words, the area of the walls as in Fig. 8 is 371/% greater per flue than the wall area in Fig. 2. The percentages of increase in flue wall area in Figs. 4 and 6 as compared to Fig. 2 is, of course, not so great as in Fig. 8, because the ribs of Figs. 4 and 6 are shallower than in Fig. 8.

In actual practice, the cross-sectional area of the flue .openings in the zone I (the bottom zone) may be nine square inches; the cross-sectionaly area in zone 2 may be' 12 square inches; the crosssectional area in zone 3 maybe 14 square inches,

and the cross-'sectional area of the iiue openings l compensate for expansion and contragtionof the gas and air passing through the checker-work.

'I'he bricks of Figs. 4 to 10 can be produced at a manufacturing cost not greatly in excess of producing the plain-faced bricks of Fig. 2, in that they can be formed by extrusion through suitable diesthat are ribbed or grooved to produce the ribs on the faces of the bricks.

` Referring now to Fig. 11, I show a brick 21 which is somewhat similar to the bricks of Figs. 4 to 10, but having the larger curved ribs 28 instead of the narrow ribs I8. 'I'he at areas 29 intermediate the ribs 25 will be engaged by the edges of adjacent bricks and the ribs not onliT provide greater contacting 'area for the gases and air, but serve to` align andsupport the 4brick, as in the other figures.

In Fig. 12, the bricks 3| have protuberances or ribs 32 extending crosswise of the bricks. These ribs serve to give increased gas-contacting area as do the ribs of the other figures, but produce a somewhat greater turbulent action on the gases andair flowing through the fiues. AIn this case, the ends of the ribs 32 of one brick will fit between curved abutting surfaces or seats 33 of adjacent ribs, so that there is a somewhatI closer interlocking engagement between the bricks of each course.

In Fig. 13, the bricks 34 have protuberances or ribs 35 which are plain on each end and which terminate short of the vertical edges of the bricks, so as to leave unribbed portions 36 at the edges of the bricks, which will t into the unribbed spaces 31 of adjacent bricks.

Referring now to Fig. 14, I show bricks 38 that are ribbed along their vertical mid portions and are beaded and grooved in their vertical edges atv 39, so that the bricks will have interlocking engagement with one another. Intermediate bricks 40 are ribbed similarly to the bricks 38, but have their verticaledges plain, and they fit between .adjacent rows of bricks 38. 'I'he flue openings 4I formed by the bricks 38 andn 40 are of the same general contour as the iiue openings in Figs. 4 to 8.

The bricks of Figs. 11 to 14 will be formed with ribs of different depth or thickness, so that the graduated iiue zones can be formed thereby, as in Figs. 1 to 8.

I claim as my invention;

1. Checker structure for furnaces, comprising vertical iiues formed of bricks arranged in superposed relation and each having a plurality of .vertical ribs so arranged and of such transverse dimensions as to materially increase the wall areas of the fiues, compared to ilues formed of planefaced bricks of similar length and width, the ribs on each brick having end-to-end abutting relation with the ribs of vertically adjacent bricks.

2. Checker structure for furnaces, comprising vertical ues formed of bricks arranged in superposed relation and each lhaving a plurality of vertical ribs so arranged and of such transverse dimensions as to materially increase the wall areas of the flues compared to flues formed of planefaced bricks of similar length and width, the checker structure being divided into zones oi graduated cross-sectional flue areas, formed by employing bricks having ribs of different lateral dimensions, and the ribs on the bricks of one zone being disposed in end-to-end abutting relation with the ribs of bricks in an adjacent zone.

JAMES E. MACDONALD. 

